PHOENIX (AP) — It was the worst loss of life for U.S. wildland firefighters in eight decades, a tragedy that killed 19 members of a Hotshot crew during an out-of-control inferno in a brush-choked canyon.

The fire prompted a strong sense of unity among everyone involved in the days after the blaze as dignitaries traveled to the site to remember the fallen and a promise to learn from the tragedy.

But one year later, few changes have been implemented among the state’s fire crews as a result of the deaths, despite an investigation that uncovered a series of communications breakdowns that doomed the 19 men and a second that blamed fire managers.

Firefighters in other parts of the country have also been unable to incorporate specific changes prompted by the deadly incident into their training, largely because Arizona investigators have been unable to reach any consensus about fault in the deaths.

The Arizona Forestry Division found that fire managers overseeing the Yarnell Hill Fire did not make major mistakes and that it isn’t clear why the Granite Mountain Hotshots left a safe zone and walked into the canyon where they were killed.

A competing report from the state’s occupational safety agency, however, blamed managers for failing to see that the town of Yarnell was essentially doomed and said they should have pulled the crews back hours before the deaths. The agency fined the Forestry Division $559,000 for failing to pull the crew.

The lack of clarity about mistakes — and what lessons might be learned — left firefighters with little to go on as they examined training and policies in the past year. The fact that all the firefighters with the crew died makes it impossible to understand their decision-making. One member of the crew was alone as a lookout, and survived, but was so far away he doesn’t know why his fellow firefighters made the decision that led to their deaths.

The state has made minor adjustments to its firefighting guidelines.

The investigation by the state forester called for testing new devices that track crews using global positioning satellites and a communications protocol requiring firefighters to tell managers when weather conditions change. Forestry officials also distributed new instructions on how ground crews should coordinate with new, large flame retardant-dropping aircraft, such as the one that was circling but unused when the Granite Mountain Hotshots were trapped.

Marshall Krotenberg, the safety agency’s lead investigator, told the Industrial Commission of Arizona in December that there should have been officers to ensure firefighters’ safety, including a planning section chief and a division supervisor. “There was no plan to move people out of the way,” he said during a hearing.

Dick Mangan, a retired U.S. Forest Service safety official who has investigated wildfire fatalities, cited the organizational mistakes as crucial errors and criticized the new communications guidelines as mere clarifications of standard practices. He also dismissed the use of GPS systems, saying the devices would be overlooked during fast moving fires such as Yarnell. “A GPS unit would have transmitted to who?” he asked.

The Yarnell Hill Fire was triggered by a lightning strike on a brush-covered mountaintop on the afternoon of June 28, 2013. The next day, a handful of crews were sent to fight the fire, but it wasn’t considered a major problem and some were released.

But as night fell, the fire grew and officials decided to call in more resources — including the Granite Mountain Hotshots. They arrived early on June 30, and headed into the hills surrounding the small former mining town.

At mid-afternoon, weather reports of a strong thunderstorm boosted fears that winds would shift and send the fire back toward Yarnell — and the 19 Hotshots deployed to the area. As the fire made its move, Granite Mountain superintendent Eric Marsh and crew Capt. Jesse Steed decided to head back to Yarnell. That’s when the flames whipped into the canyon, trapping the crew. A 20th member of the Hotshots, acting as a lookout, made a dash to safety.

Dugger Hughes, a battalion chief who oversees a Hotshot crew for the Northwest Fire district in southern Arizona, said not much can be learned from the fire because no one knows the thinking of Marsh and Steed.

“The investigation, both of them, I’ve read them and re-read them numerous times. There were some decisions made, and I’m not sure anybody will ever know why,” Hughes said. “A lot of fatality incidents there are some real vivid lessons-learned that come from them. This isn’t one of them.”

Kris Bruington, superintendent of the Lone Peak Hotshots in Utah, says other than reinforcing the need to focus on time-tested basics of lookouts, communication, safety zones, escape routes and every crew member’s right to speak up about safety concerns, there’s little to learn.

“With the Yarnell reports it’s tough, there’s nothing that they can say ‘hey, this is what happened, and this is why it happened,” Bruington said. “Because there’s just nobody left to say, ‘Well, this is what we were talking about 30 minutes before this happened.'”

The state is appealing the more than $550,000 fine, and a hearing is scheduled for August. The state Forestry Division has declined to comment on the fire or the investigations.

Even Gov. Jan Brewer tiptoes about the issue.

“I don’t want to weigh in on litigation issue, because it taints it and creates bigger issues for Arizona,” Brewer said in an interview this month. “There were reports done by two or three different agencies, and they did a good job. It was an unfortunate, horrific tragedy that took place, emotions were wild. And I think that eventually it will come to the conclusion that certain, possibly different methods, techniques, call it what you wish, will be improved.”